Citric acid, a sour substance is naturally present to a large extent in almost all sour fruits like citrus fruits, lemon, pineapple etc.

On commercial scale, citric acid is produced by fermentation of dextrose obtained by corn processing or sugarcane molasses. Citric acid can also be produced from the secondary juice.

The process of producing citric acid by fermentation consists of the following stages -

Preparation of fermentation substrate.

Fermentation

Isolation of citric acid from the fermented mash.

Purification of the citric acid raw solution.

Crystallisation of citric acid.

Uses of citric acid -

In Food beverages -

Citric acid is widely used in food and beverages. It is used as a flavour enhancer and modifier and also as a preservative. Because of low pH, citric acid can prevent growth of micro-organisms that might cause food poisoning. It also prevents rancidity and discolouration of foods as an anti-oxidant for fish, frozen or canned vegetables, fruits & seafood. Citric acid is also used as a buffer during various stages of the food processing, in cheese spreads, jellies and beverages. Infact, beverages are the main users of citric acid.

In Industrial and household detergents -

Many industrial applications of citric acid and sodium citrate are not only based on their acidic properties, but also upon their powerful action on metals for removing rust and scale formations. Chemical cleaning formulations meant for cleaning boiler equipments, power generation parts, reactors and chemical processing equipments contain citric acid or its salts. In tanning, citric acid is used to prevent swelling of hide. In all household cleaning liquids and detergents, citric acid is widely used. It is also used in dyeing of fabrics.

Uses in pharmaceuticals and cosmetics -

The pharmaceutical industry uses citric acid extensively because of its safe and non-toxic nature, pleasant acid taste, high water solubility and buffering properties. It is used in tablets to improve solubility, in artificial sweeteners to dissolve rapidly in pharmaceutical preparations as a flavouring and stabilizing agent. It is used with fruit flavours to mask bitter medicinal flavours. It is used in chewing tablets, syrups and many other medicines. n cosmetics, citric acid is used for hair conditioners and shampoos. It is also used in lotions, facial creams, tooth pastes, creams etc.